Fluorescent penetrant indication (FPI) inspection utilizes a fluorescent dye applied onto a non-porous surface of a work piece. After removing a bulk of the dye from the surface, illuminating the surface in ultraviolet radiation in a dark room causes residual amounts of the dye within discontinuities of the work piece to emit a fluorescent glow that contrasts with the dark background, indicating the presence of the discontinuities. Each discontinuity may be a defect in the surface of the work piece, such as a crack, a chip, micro shrinkage, or spalling (e.g., flaking). The current protocol for FPI inspection is purely manual. For example, an inspector sits in a dark room or tent and manipulates an ultraviolet light source and/or a work piece to illuminate the work piece with ultraviolet light. Upon initial detection of a potential defect on the work piece, the inspector may brush or wipe the work piece to remove any dust and/or debris or other surface contamination that could represent a false positive. Then the inspector views the work piece under the ultraviolet light for a second time to determine the presence or absence of any defects on the surface of the work piece. If the inspector determines that the work piece has one or more defects, the inspector may designate the work piece for repair or may discard (e.g., scrap) the work piece.
The current manual process of FPI inspection is subjective and inconsistent. For example, the process is subject to the inherent human bias and/or error of the particular inspector performing the inspection. Although there may be adopted guidelines or rules for the inspectors to follow when determining whether to pass a work piece as satisfactory, send the work piece for repair, or discard the work piece, two different inspectors may apply the guidelines differently based on bias and/or error. It is possible that one inspector may decide to scrap a work piece that another inspector in the same situation would decide to pass or to repair.
Besides classifying specific work pieces for immediate use, repair, or discard, there may be limited information (e.g., data) collected during the current manual process for FPI inspection. For example, limited, if any, information may be collected and recorded regarding the defects which could be used for improving quality control and consistency. Such information may include the type of defects (e.g., cracks, spalling, chips, etc.), the size and/or shape of the defects, and number of defects, the location of the defects, etc.
Furthermore, the current manual process for FPI inspection is inefficient and also uncomfortable for the inspector. For example, it may be uncomfortable and/or undesirable for the inspector to spend extended periods of time in a dark room or tent manipulating an ultraviolet light source and/or work pieces covered in a fluorescent dye to inspect the work pieces.